Selective-position control mechanism



Dec. 9, 1947. E. J. STEIN 2,432,349

SELECTIVE-POSITION CONTROL MECHANISM Filed Aug. 1, 1944 INVENTOR EDWARDJ. STEIN AT RNEY tuning adjustments.

Patented Dec. 9, 1947 UNITED STATES PATENT OFFICE SELECTIVE-POSITIONCONTROL MECHANISM I Edward J. Stein, Bellcrose Manor, N. Y.. assignor,by mesne assignments, to Hazeltine Research, Inc., Chicago, 111., acorporation of Illinois Application August 1, 1944, Serial No. 547,599

12 Claims. 1

' This invention is directed to a selective-position control mechanism.While being subject to a variety of applications, the invention isespecially suited for controlling the variable element of an adjustablytuned circuit and will be described in ductor and effective to determinethe-apparent inductance thereof in accordance with the degree of couplintherebetween. One form of control mechanism, employed to vary theposition of the tuning slug and thereby vary the inductance andoperating frequency of the tuned circuit, includes a threaded shaft toone, end of which the tuning slug is secured. A control knob affixed tothe opposite end of the shaft facilitates accurate While such prior artcontrol mechanisms permit the tuned circuit to be adjusted over a givenrange of operating frequencies, they generally do not include provisionsfor arresting the control mechanism at preselected control positions, asis required to adjust the tuned circuit rapidly and accurately to one ormore desired operating frequencies within its range. In someinstallations, such a feature is highly desirable.

Other control mechanisms enabling a tuned circuit to be adjusted over agiven operating frequency range and including provisions for rapidlyadjusting the circuit to one or more predetermined frequencies withinthe range have already chanical complexities, these arrangementsrepresent a substantial mass or weight which may be objectionable inapplications where the weight factor is important, as in air-borneinstallations.

It is, therefore, an object of the invention to provide a selectiveposition control mechanism which is not subject to one or more of theabovementioned limitations of prior art arrangements.

It is another object of the invention to provide an improved selectiveposition control mechanism having a simplified and inexpensivemechanical construction.

It is another object of the invention to provide an improved controlmechanism which permits f continuous'adjustment of a controlled element,

and includes provisions for quickly and'accuratel'y effectingpreselected adjustments of the controlled element. A selective-positioncontrol mechanism, in ac-' cordance with the invention, comprisesarotatable shaft to be coupled to a controlled element for exertingthereon a control effect determined by the angular displacement of theshaft with respect to a reference position and means for angularlydisplacing the shaft with respect to its reference position. The controlmechanism is provided with a first nonresilient stop device includingprovisions for registering with a second resilient stop device. A secondapproximately circular stop device is provided in nested relation withthe first stop device and comprising a resilient portion includingprovisions for registering with the first stop device to arrest theshaft in a preselected control position and also including anonresllient portion. At least one of the first and second stop devicesis angularly adjustable to a corresponding preselected position withrespect to the above-mentioned reference position independently of theshaft displacement. Additionally, the control mechanism comprises meansfor supporting the first and second stop devices for relative rotationtherebetweenin response to the angular displacement of the shaft and forpositioning the stop devices with respect to one another so that uponrelative rotation therebetween the registering provisions of theresilient portion of the second stop device exert a locking effect onthe first stop device to arrest the shaft in the aforesaid preselectedposition.

For a better understanding of the present invention, together with otherand further objects thereof, reference is had to the followingdescription taken in connection with the accompanying drawing, and itsscope will be pointed out in the appended claims.

In the drawing, Fig, 1 is a side elevational view, partly in crosssection, of a'control mechanism in accordance with the invention; Fig. 2comprises a cross-sectional view taken as indicated by directionalarrows 2--2 of Fig. 1; while Fig. 8

is an isometric representation of one component of the Fig. 1arrangement.

Referrirg now more particularly to Fig. 1 of the drawing, there isillustrated a selective-position control mechanism embodying theinvention utilized for controlling an adjustably tunedcircuit. The tunedcircuit may constitute a component of a wave-signal translatingapparatus, such as a wave-signal receiver, but since the invention maybe completely understood from a consideration of .the adjustment of thetuned circuit alone, the

thermoplastic resin. The mounting portion 16 4 to a supportingstructure. The particular manner in which the tuned circuit is securedto mounting plate 20 will be made clear presently. Considering now theselective-position control mechanism of Fig. 1, the illustratedarrangement comprises a rotatable shaft 25 to be mechanically coupled tothe controlled. element, plunger l5, for exerting thereon a controleffect determined by the angular displacement of the shaft with respectto a reference position, identified hereinafter. Shaft 25 is rotatablewithin and supported by an externally threaded bushing 26 which projectsthrough a suitable aperture in mounting plate 20. A flange collar 21 isformed of the coil form has an increased diameter and an internal keywayI1 is milled therein for a purpose to be described hereinafter. Acoil-retaining groove II in the form of a continuous spiral is milledinto coil form ID and the wall thickness of the coil form is,preferably, as small as practical. The inductor L, per se, consists of apreformed coil having an inner diameter slightly less than the diameterof groove H. The preformed coil is, preferably, made of a resilient'material such as hard drawn brass, silver plated to have an improvedconductivity characteristic. The cross section of the coil conductor andthe material from which it is formed are selected.

with reference to the coildiameter so that the free ends l2 and I3thereof have sufficient selfrigidity to permit direct connection -toother circuit components of the equipment. In assembling the describedinductor. arrangement, the preformed coil, is threaded onto coil form Itwith the convolutions thereof received by groove ii. Due to theresiliency of the coil and the relative dimensions of the coil diameterand groove diameter, the coil convolutions firmly engage groove II andsecurely lock the coil in a desired position on form l0.

The described tuned circuit is adjustable over a givenrange of operatingfrequencies through a tuning core or slug M which is freely movablewithin coil form l0. Tuning slug [4 may be of.

either a magnetic or non-magnetic material, depending upon thevariations of inductance required. As is well understood in the art,such inductance of inductor L in accordance with the couplingtherebetween. Where the slug is of magnetic material, the inductanceincreases with this coupling, while the converse effect is obtainedthrough the use of a nonmagnetic mastituting the element controlled bythe control mechanism presently to be described.

The tuned circuit L, C is supported by a mounting plate 20 having aright-angle flange portion 2| in which apertures 22 are provided for thepurpose of securing the mounting plate 'a tuning slug is effective tovary the apparent integrally on one end of bushing 26 for receiving themounting portion iii of coil form In, these elements being lockedtogether through one or more machine screws 28.

Shaft 25 is coupled to controlled element [5 through a cam cylinder 30having a closed end 3! which is fixed to one end of shaft '25. A camtrack 32 in the form of an Archimedean spiral is mllledinto the camcylinder. The end portions of the cam trackare indicated at 32a and 32b.'The controlled element 15 is received by the open end of cam cylinder30 and carries a cam-following pin 33 which projects through cam track32 into engagement with keyway H of the coil form portion l6. Keyway l1locks pin 33' against rotation while permitting the pin to move in anaxial direction. A coil spring 34 interposed between the closed end ofcam cylinder 30 and the adjacent end of plunger 15 retains pin 33incontact with the cam track.

A-control knob 40 secured to the free end of shaft 25 through a setscrew 4! constitutes means for angularly displacing the shaft withrespect to a reference position. The maximum angular displacement of theshaft is limited to a predetermined value by the engagement of pin 33with the end portions 32a and 32b of cam track 32. Cam portion 32adetermines the above-men tioncd referenceposition of shaft 25, while thealternate cam portion 32b determines the maximum angular displacement oftheshaft. I This maximum displacement in the illustrated arrangement isapproximately 360' degrees.

The control mechanism also includes a first non-resilient stop device 43including provisions for registering with a second resilient stopdevice. This first stop device comprises a circular member 45 having ahubportion 46 and an annular shoulder 41. Supported upon annularshoulder "41 there is at least one stop projection or element 48 havinga wedge-shaped portion 49, Fig. 2, for engaging with a cooperatingresilient stop device. Preferably, a plurality of such stop projections48 are included in device 43 for individually engaging with acooperating resilient stop device.

A second approximately circular and cooperating stop device 56,represented in Fig. 3, is included in the control mechanism. This stopdevice comprises a cylindrical member 50 closed at one end and having anarcuate slot 5| extending over a substantial portion of thecircumference thereof. Preferably, the slot is milled adjacent to theclosed end of the cylinder and extends throughout a major portion of thecircumference to provide the second stop device 56 with a L resilientportion 52 and a nonresilient portion 53, The resilient portion 52includes provisions for registering with the first stop device to arrestshaft 25 in a preselected control position. More particularly, a stoprecess 54 is provided in the inner wall of resilient portion 52, havinga configuration which is complementary to portion 49 of stop elements 48included in the first-described stop device 43. This stop recess iseffective to register with each of the plurality of stop pro-- jections48 of device 43 to arrest shaft 25 in a corresponding plurality ofpreselected control positions.

The control positions of shaft 25 resulting from registration of thestop provisions included in devices 4'3 and 56 may be preselected byarranging at least one of such stop devices or its stop provisions to beadjustable with respect to the reference position of shaft 25independently of the shaft displacement. For this purpose, stopprojections 48 of device 43 are individually adjustable to preselectedpositions with respect to the reference shaft position. This adjustmentis accomplished through machine screws 44 which secure stop projections48 in adjustably fixed positions upon the annular shoulder 41 ofcircular member 45. f

The control arrangement is completed into one assembly through means forsupportin'g'the described first and second stop devices for relativerotation therebetween in response 'to the angular displacement of theshaft and for positioning the stop devices with reference to, oneanother so that upon such relative rota-tion resilient portion 52 of thesecond stop device exerts a greater pressure than the nonresilientportion 53 exerts on the first stop' device; To achieve such arelationship in the supporting and positioning of the first and secondstop devices, the closed end of stop'device 56 has an aperture 55 whichis offset in the direction of the central portion of resilient section52. In other 1 words, the radial distance from the center of aperture55',to the mid-portion of resilient section 52 is less than the radialdistance to the corresponding portion of nonresilient section 53. Stopdevice 56 is, supported by means of aper-. ture 55 upon threaded bushing26. A look nut 68 engages the threaded bushing and is tightened to clampthe bushing and stop device 56 into one stationary assembly withmounting plate 28;

Suitable spacing washers GI, 62 are includedin device 56. The drivingconnection to stop device 43 is a transverse pin 63 projecting throughhub portion 46 of the stop device and shaft 25. The relativeproportioning of the described first and second step devices and theeccentricity of aperture are such that upon relative rotation betweenthe first and second stop devices the resilient portion 52 of the secondstop device 55 exerts a greater pressure on the stop projections 48 offirst device 43 than is exerted thereon by the non-resilient portion 53of device 56.

In considering the operation of the described control mechanism, thefunction of stop members 43 and 58 will inkially be neglected and itwill be assumed that contrwgb 40 is adjusted so that pin 33 isinengagemen ith cam portion 32a. As indicated above, this conditionreprethe assembly. The second stop device 43, on the other hand, issupported directly" by shaft 25 tobe angularly driven thereby withrespect to stop placed in the same sense with respect to its referenceposition. Such displacement of shaft 25 results in the application of acontrol effect upon plunger [5 through the agency of cam track 32, pin33 and keyway H. The control effect manifests itself as a lateraldisplacement of pin 33, plunger l5 and tuning slug l4, advancing theseelements a corresponding amount in the direction of inductor L so as toincrease the degree of coupling between the inductor and its tuningslug. The increased coupling results in a decrease in apparentinductance of inductor L and a proportional increase in the operatingfro quency of tuned circuit L, C. In the limiting condition when shaft25 has its maximum angular displacement, the degree of coupling betweenthe inductor andits tuning slug is a maximum and the operating frequencyof the tuned circuit likewise has its maximum value. Thus, the controlmechanism is effective continuously to adjust a the operating frequencyof the tuned circuit L, C over a given range of operating frequencies.Stop members 43 and 56 permit the operating frequency to be establishedaccurately and rapidly to predetermined desired frequencies within thisrange in the following manner,

A particular setting of a given stop projection 4'8 of stop device 43represents a predetermined angular displacement with respect to thereference position of shaft 25. Likewise, a given angular displacementof the shaft represents a given control effect which causes tuning slugi4 to have a predetermined degree of coupling with inductor L resultingin a given operating frequency of the tuned circuit. Therefore, stopprojections 48 are adjusted to preselected positions around theperiphery of member 45. Having thus selectively positioned stopprojections 48, control knob 40 is rotated until a particular stopprojection 48 registers with stop recess 54 of resilient portion 52 ofstop device 56, arresting shaft 25 in a corresponding preselectedcontrol position to establish the desired operatin frequencyof the tunedcircuit. Since portion 52 of stop device 56 is resilient, any of stopprojections 48 may be rotated beyond stop recess 54 to effectregistration of a particular stop device 48 wlth'recess54. Hence, shaft25 may be arrested in a preselected control position corresponding tothe adjustment of a particular. stop projection '48, irrespective of theprevious setting of control sents the reference position of shaft 25 inwhich cam 32 causes tuning slug 14 to be withdrawn from inductor L so asto have substantially zero. coupling therewith. For this condition, theinductor exhibits its natural value of inductance and tuned circuit L, Chas its minimum operating frequency. As control knob 40 is rotated in aclockwise direction, shaft 25 is angularly dis- If desired, anadditional stop device having the same general construction as device 56may be included in the control arrangement forcooperation with stopprojections 48 of stop device .43. Increasing the stop elements in sucha fashutilized to control a variable condenser or any other controlledelement.

, The control mechanism of the invention will be seen to comprise arelatively few, light mechanica1 elements. Accordingly, it substantiallyarrest said shaft in avoids the mechanical complexities of the prior artarrangements mentioned above. Additionally, the control mechanism isinexpensive toconstruct and represents a small mass, renderin itsuitable for air-borne installations.

While there has been described What is at present considered to be thepreferred embodiment of this invention, it will be obvious to thoseskilled in the art that various changes and modifications may be madetherein withoutdeparting from the invention, and it is, therefore, aimedin the appended claims to cover all such changes and modifications asfall within the true spirit and scope of the invention.

What is claimed is:

1. A selective-position control mechanism comprising, a rotatable shaftto be coupled to a-controlled element for exerting thereon a controleffect determined by the angular displacement of said shaft with respectto a reference position, means for angularly displacing said shaft withrespect to said reference position, a first nonresilient stop deviceincluding provisions for registering with a second stop device. a secondapproximately circular stop device in nested relation with said firststop device comprising a re silient portion including provisions forregistering with said first stop device to arrest said shaft in apreselected control position and including a nonresilient portion, atleast one Of said stop devices being angularly adjustable to acorresponding preselected position with respect to said referenceposition independently of said shaft displacement, and means forsupporting said stop devices for relative rotation therebetween inresponse to said displacement of said shaft and for positioning saidstop devices with respect to one another so that upon relative rotationtherebetweensaid registering provisions of said resilient portion ofsaid second stop device exert a locking effect on said first stop deviceto arrest said shaft in said preselected position,

2. A selective-position control mechanism comprising, a; rotatable shaftto be coupled to a controlled element for exerting thereon a controlefiect determined by the angular displacement of said shaft with respectto a reference position, means for angularly displacing said shaft withrespect to said reference position, a. first nonresilient stop deviceincluding provisions for registering with a second stop device, a secondapproximately circular stop device .in nested relation with said firststop device comprising a resilient portion including provisions forregistering with said first stop device to arrest said shaft in apreselected control position and including a nonresilient portion, atleast one of said stop devices being angularly adjustable to acorrespondin preselected position with respect to said ref erenceposition independently of said shaft displacement, and means forsupporting said stop devices for relative rotation therebetween inresponse to said displacement of said shaft and for ccentricallypositioning said stop devices with respect to one another so that uponrelative rotation therebetween said registering provisions of saidresilient portion of said second stop device exert a locking effect onsaid first stop device to said preselected position.

- 3. A selective-position control mechanism comprising, a rotatableshaft to be coupled to a controlled element for exerting thereon acontrol effect determined by the angular displacement of said shaft withrespect to a reference position, means for anguiarly displacing saidshaft with respect to said reference position, a first nonresilient stopdevice including at least one stop projection for registering with asecond stop device, a second approximately circular stop device innested relation with said first stop device comprising a resilientportion having at least one stop recess for registering with said stopprojection of said first stop device to arrest said shaft in apreselected control position and including a nonresilient portion, atleast one of said stop devices being angularly adjustable to acorresponding preselected position with respect to said referenceposition independently of said shaft displacement, and means forsupporting said stop devices for relative rotation therebetween inresponse to said displacement of said shaft and for positioning saidstop devices with respect to one another so that upon relative rotationtherebetween said stop recess of said resilient portion of said secondstop device exerts a locking effect on said first stop device to arrestsaid shaft in said preselected position.

4. A selective-position control mechanism comprising, a rotatable shaftto be coupled to a controlled element for exerting thereon a controleffect determined by the angular displacement of said shaft with respectto a reference position, means for angularly displacing said shaft withrespect to said reference position, a first nonresilient stop deviceincluding provisions for registering with a second stop device andangularly adjustable to a preselected position with respect to saidreference position independregistering with said first stop device toarrest said shaft in a corresponding preselected control position andincluding a nonresilient portion, and means for supporting said stopdevices for relative rotation therebetween in response to saiddisplacement of said shaft and for positioning said stop devices withrespect to one another so that upon relative rotation therebetween saidregistering provisions of said resilient portion of said second stopdevice exert a locking effect on said first stop device to arrest saidshaft in said preselected position.

5. A selective-position control mechanism comprising, a rotatable shaftto be coupled to a controlled element for exerting thereon a controleffect determined by the angular displacement of said shaft with respectto a reference position, means for angularly displacing said shaft withrespect to said reference position, a first nonresilient stop deviceincluding a plurality of stop elements for individually registering witha second stop device and individually adjustable to a preselectedposition with respect to said reference position independently of saidshaft displacement, a second approximately circular stop device innested relation with said first stop device rotation therebetween saidregistering provisions of said resilient portion of device successivelyto arrest said shaft in said plurality of preselected positions.

6. A selective-position control mechanism comprising, a rotatable shaftto be coupled to a controlled element for exerting thereon a controleffect determined by the angular displacement of said shaft with respectto a reference position, means for angularly displacingsaid shaft withrespect to said reference position, a first nonresilient stop deviceincluding provisions for reg istering with asecond stop device, a secondapproximately circular stop device in nested relation with said firststop device comprising a cylindrical member having an arcuete slotextending over a substantial portion of the circumference thereof toprovide a resilient portion and a nonresilient portion and havingprovisions in said resilient portion for registering with said firststop device to arrest said shaft in a preselected control position, atleast one of said stop devices being angularly adjustable to acorresponding preselected position with respect to said referenceposition independently of said shaft displacement, and means forsupporting said stop devices for relative rotation therebetween inresponse to said displacement of said shaft and for positioning saidstop devices with respect to one another so that upon relative rotationtherebetween said registering provisions of said resilient portion ofsaid second stop device exert a locking effect on said first stop deviceto arrest said shaft in said preselected position.

'7. A selective-position control mechanism comprising, a rotatable shaftto be coupled to a controlled element for exerting thereon a controleffect determined by the angular displacement of said shaft with respectto a reference position, means for angularly displacing said shaft withrespect to said reference position, a first nonresilient stop deviceincluding provisions for registering with a second stop device, a secondapproximately circular stop device in nested relation with said firststop device comprising a cylindrical member having an arcuate slotextending over a major portion of the circumference thereof to provide aresilient portion and a nonresilient portion and having provisions insaid resilient portion for registering with said first stop device toarrest said shaft in a pro-- selected control position, at least one ofsaid stop devices being angularly adjustable to a correspondingpreselected position with respect to said reference positionindependently of said shaft displacement, and means for supporting saidstop devices for relative rotation therebetween in resaid shaft withrespect to a reference position,

means for angularly displacing said shaft with respect to said referenceposition, a first non resilient stop device including provisions forregistering with a second stop device, a second approximately circularstop device in nested relation with said first stop device comprising acylindrical member closed at one end and having an arcuate slotextending over a substantial pordevices with respect to one another sothat upon relative rotation therebetween said registering provisions ofsaid resilient portion of said second stop device exert a locking effecton said first stop device to arrest said shaft in said preselectedposition.

9. A selective-position control mechanism comprising. a rotatable shaftto be coupled to a controlled element for exerting thereon a controleffect determined by the angular displacement of said shaft with respectto a reference position, means for angularly displacing said'shaft withrespect to said reference position, a first nonresilient stop deviceincluding provisions for reg-' istering with a second stop device, asecond approximately circular stop device in nested relation with saidfirst stop device comprising a cylindrical member closed at one end andhaving an arcuate slot adjacent said closed end extending over asubstantial portion of the circumference thereof to provide a resilientportion and a nonresilient portion and having provisions in saidresilient portion for registering with said first stop device to arrestsaid shaft in a preselected control position, at least one of said stopdevices being angularly adjustable to a corresponding preselectedposition with respect to said reference position independently of saidshaft displacement, and means for supporting said stop devices forrelative rotation therebctween in response to said displacement of saidshaft and for positioning said stop devices with respect to oneanother'so that upon relative rotation therebetween said registeringprovisions of said resilient portion of said second stop device exert alocking effect on said first'stop device to arrest said shaft in saidpreselected position.

10. A selective-position control mechanism comprising, a, rotatableshaft to be coupled to a controlled element for exerting thereon acontrol effect determined by the angular displacement of said shaft withrespect to a reference posi-.

tion, means for angularly displacing said shaft with respect to saidreference position, a first nonresilient stop device includingprovisions for registering with a second stop device, a secondapproximately circular stop device in nested relation with said firststop device comprising a resilient portion including provisionsforregistcring with said first stop device to arrest said shaft in apreselected control position and including a nonresilient portion, atleast one of said stop devices being angularly adjustable to acorresponding preselected position with respect to said referenceposition independently of said shaft displacement,- and means forsupporting said stop devices so that said first stop device is angularlydriven with respect to said second stop device by said shaft and forpositioning said stop devices with respect to one another so that uponrelative rotation therebetween said registering provisions of saidresilient portion of said second stop device exert a locking effect onsaid first stop device to arrest said shaft in said preselectedposition.

11. A selective-position control mechanism comprising, a rotatable-shaftto be coupled to a controlled element for exerting thereon a controleffect determined by the angular displacement of said shaft with respectto a reference position, means for angularly displacing said shaft withrespect to said reference position, a first nonresilient stop deviceangularly driven by said shaft and including provisions for registeringwith a second stop device, a second stationary and approximatelycircular stop device in nested relation with said first stop devicecomprising a resilient portion including provisions for registering withsaid first stop device to arrest said shaft in a preselected controlposition and including a non-resilient portion, at least one of saidstop devices being angularlyadjustable to acorresponding preselectedposition with respect to said reference position independently of saidshaft displacement, and means for positioning said stop devices withrespect to one another so that upon relative rotation therebetween saidregistering provisions of said resilient portion of said second stopdevice exert a locking effect on said first stop device to arrest saidshaft in said preselected position.

12. A selective-position control mechanism comprising, a rotatable shaftto be coupled to a controlled element for exerting thereon a controleffect determined by the angular displacement of said shaft with respectto a reference 2 position, means for angularly displacing saidshaft-with respect to said reference position, a first nonresilient stopdevice supported by said shaft for rotation therewith and includingprovisions for registering with a second stop device, a secondstationary and approximately circular stop device in nested relationwith said first stop device comprising a resilient portion includingprovisions for registering with said first stop device to arrest saidshaft in a preselected control position and including a nonresilientportion, at least one of said stop devices being angularly adjustable toa corresponding preselected position with respect to said referenceposition independently of said shaft displacement, and means forpositioning said stop devices with respect to one another so that uponrelative rotation therebetween said registering provisions of saidresilient portion of said second stop device exert a locking effect onsaid first stop device to arrest said shaft in said preselectedposition.

EDWARD J. STEIN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

